The compounds of formula (Ia, b) belong to the class of esters of glycidic acid. Preferred examples of these compounds when used in accordance with the invention are the methyl and the ethyl esters, viz. methyl 3-methyl-3-(norbornen-5-yl)-glycidate and ethyl 3-methyl-3-(norbornen-5-yl)-glycidate, which compounds develop the most pronounced fragrance.
Compounds possessing a chemical structure analogous to that of compounds (Ia, b) and which have been described in the art as possessing odoriferous properties include acetyl-norbornene of formula ##STR4## (see Japanese Pat. No. 71 30 184), and 5-(2-alkoxycarbonylvinyl)-bicyclo[2.2.1]hept-2-ene of formula ##STR5## (see DE-OS No. 21 63 770 published on July 5, 1973). No well defined description has been given with respect to the olfactive properties of the first of the above defined compounds; whereas the cited bicyclo-heptene compound is described as possessing a fruity odor reminiscent of that developed by melon. When I tried to synthesize 5-(2-ethoxycarbonylvinyl)-bicyclo[2.2.1]hept-2-ene in accordance with the described method, instead of the expected product I obtained a complex mixture containing about 60% of the pure compound, which upon isolation and purification did not demonstrate, contrary to the prior art teaching, any melon-like smell.
I have now discovered that compounds (Ia, b) present, in contradistinction, a fruity fragrance whose melon-like character is very distinct and perfectly reproducible. Consequently, the compounds of formula (Ia, b) present a major interest for perfumery, not only for the manufacture of perfume compositions destined to the preparation of perfumes, but also as active ingredients for perfuming various articles, such as soaps, cometics, shampoos, body deodorizers, air fresheners, waxes, detergents or household materials in general.